perhaps my previous haiga demands a few aditional words.
the burrs in the photo are those of a horse chestnut
(aesculus hippocastanum), a deciduous tree native to the balkans area and quite common in the local parks and alleys. its nuts (conkers) are not edible to humans, although they are used in home medicine (and, i suspect, in cosmetics and pharmacy), but i have seen the local corvids feeding on the conkers in winter.
so, basicaly, the haiku is just an observation. the burrs are wide open and empty, so the nuts must have fallen under the tree and are now covered with a layer of snow. the crow, being the clever bird that it is, knows it can find the nuts under the snow, so it pierces it with its beak, probing it, searching for food...
of course, this is just one of the possible interpretations, and it's always a compliment for te author if the readers find other meanings in their work. the images are rather sharp, which is how i wanted them to be (winter is a harsh season after all), and the crow itself evokes darker feelings so anything is eligible :)